The basic function of circuit breakers, also referred to as relays or contactors, consists of switching high electric power outputs in a load circuit with the aid of a comparatively small current, this being a control current. The current in the load circuit is several times greater than the control current.
One problem that arises with circuit breakers when high power outputs are switched is that arcs can develop during switching of the switch contacts and can result in wear of the switch contacts. These switch contacts are made of copper or silver, for example, in the circuit breakers known from the prior art. In particular at high voltages and currents, arcs inevitably develop between the switch contacts to be separated. These arcs are usually extinguished by the additional use of quenching gas or quenching magnets, for example, so as to achieve safe separation of the switch contacts and to prevent the arcs from jumping to neighboring components of the circuit breaker and damaging these. This, however, is often complex to implement, in particular when the circuit breaker is used in a motor vehicle.
The load currents that can flow with the use of circuit breakers in a vehicle can be as high as 1500 amperes or higher. When such a high load current flows as the contacts are being separated by the circuit breaker, the number of make-and-break cycles of circuit breakers used today is limited due to the design thereof. The separation of the switch contacts of such a circuit breaker, the contacts of which usually comprise copper or silver, takes place just a few times with an isolating current of this magnitude since the isolating current normally causes severe damage to the switch contacts of the circuit breaker. After a few make-and-break cycles, the circuit breaker must then already be replaced again, which increases the maintenance complexity of such circuit breakers.